In the article “Glycinergic and GABAergic Synaptic Activity Differentially Regulate Motoneuron Survival and Skeletal Muscle Innervation,” by Glen B. Banks, Refik Kanjhan, Stefan Wiese, Matthias Kneussel, Loke M. Wong, Gregory O'Sullivan, Michael Sendtner, Mark C. Bellingham, Heinrich Betz, and Peter G. Noakes, which appeared on pages 1249-1259 of the February 2, 2005 issue, Figures 1G,H, 2C,D, 3E,F, 5B-E, and 7 are missing their y-axis numbers. Corrected versions of Figures 1, 2, 3, 5, and 7 are printed here.
Figure 1.
Lateral motor axon extension is restricted in the diaphragm in gephyrin-deficient mice. Motor axon branches (green) and acetylcholine receptor clusters (red) in the left hemi-diaphragms in wild-type (+/+) and gephyrin-deficient (-/-) mice at E18.5 (A, B) and E16 (E, F) are shown. Quantification of the distance axons extending from the nerve trunk (mean ± SEM) for wild-type (C, E18.5; G, E16) and gephyrin-deficient (D, E18.5; H, E16) mice taken from four litter-matched pairs is also shown. In graphs C, D, G, and H, the left and right y-axes relate to the medial and lateral number of branches, respectively. Scale bars: A, B, 200 μm; E, F, 50 μm.
Figure 2.
The number of axon branches and neuromuscular synapses is reduced in the diaphragm of gephyrin-deficient mice. Motor axon branches (green) and postsynaptic acetylcholine receptor clusters (red) in wild-type (A, +/+) and gephyrin-deficient (B, -/-) diaphragms at E18.5 are shown. Note that there were fewer axon bifurcations and neuromuscular synapses in the -/- compared with the +/+. Scale bar, 100 μm. C shows the total number (mean ± SEM) of axon bifurcations in the most ventral 1.2 mm of the left hemi-diaphragm in wild-type (white bars) and gephyrin-deficient (black bars) mice taken from four litter-matched pairs at E18.5 and E16. D shows the number (mean ± SEM) of neuromuscular synapses in the same regions. *p < 0.05; **p < 0.01; n = 4; Student's t test.
Figure 3.
Increased innervation of limb muscles in gephyrin-deficient mice. Motor axon branches (green) and acetylcholine receptor clusters (red) in the gluteus maximus muscle in wild-type (A, E18.5; C, E16; +/+) and gephyrin-deficient (B, E18.5; D, E16; -/-) mice are shown. E and F show the numbers (mean ± SEM) of gluteus maximus NMJs and branch bifurcations over the same muscle region for wild-type (white bars) and gephyrin-deficient (black bars) E18.5 and E16 mice. There were significantly more neuromuscular synapses and branch bifurcations in the gluteus maximus muscles from gephyrin-deficient mice compared with wild-type controls. *p < 0.05; **p < 0.01; n = 5; Student's t test. Scale bars: A, B, 100 μm; C, D, 50 μm.
Figure 5.
Regional differences in spontaneous and drug-induced motor activity in wild-type (+/+) and gephyrin-deficient (-/-) mice. A, An example of the differences in nerve burst activity from hypoglossal (XII) and lumbar (L5) ventral rootlets recorded from +/+ and -/- brainstem-whole spinal cords. B, Mean nerve burst frequency for L5 (+/+, n = 9; -/-, n = 7) and hypoglossal (+/+, n = 6; -/-, n = 4) nerve recordings showing a significant decrease in lumbar nerve burst frequency and an increase in hypoglossal nerve burst frequency. C, Mean nerve activity per minute (calculated as total nerve burst charge per minute) for lumbar (+/+, n = 9; -/-, n = 7) and hypoglossal (+/+, n = 6; -/-, n = 4) nerve recordings, showing a significant decrease in lumbar mean nerve activity and an increase in hypoglossal nerve activity. *p < 0.05; **p < 0.01; Student's t test. Effects of glycine and GABA on nerve burst frequency are significantly different for lumbar and hypoglossal nerve activity in +/+ and -/- mice. Mean burst frequency during drug application is shown as a percentage of burst frequency for 10 -20 min before drug application (indicated by dashed line and referred to in text as “control”). D, GABA (100 μm) application increases mean L5 burst frequency and decreases XII burst frequency in +/+ mice (white bars); these effects are enhanced in -/- mice (black bars). Two-way ANOVA; p < 0.05. E, Glycine (100 μm) application also increases mean lumbar burst frequency and decreases hypoglossal nerve burst frequency in +/+ mice (white bars); these effects are abolished in -/- mice (black bars). Two-way ANOVA; p < 0.05.
Figure 7.
In vitro differentiation of motoneurons is unaltered in gephyrin-deficient mice. Shown is mean survival of motoneurons isolated from E14 wild-type (+/+; white bars) and gephyrin-deficient (-/-; black bars) embryos after 5 d in culture, grown in Neurobasal medium only (no factor) or in Neurobasal medium supplemented with one of the following neurotrophic factors: BDNF, GDNF, or CNTF. There was no significant difference in the survival of motoneurons isolated from wild-type or gephyrin-deficient mice under any of these treatments.